I suggest you look at the reply I have just posted to AllBoysHere
for the record, I am not professionally involved in autism in any way, however I do run a group for adult autistics and it is something I have studied and am continuing to study as a postgraduate.
I should have answered that some of those things do sound like traits one sees in autistic children.
It is a good idea to get it professionally evaluated as there are various interventions which can help when it comes to education, but above all be careful what you read and avoid "snake oil" like the plague, there are many out there who will claim that autism is the worst disability in the world (yes they would have it that it is worse than ALS which is the one that scares the pants off me) and then tell you that x y or z can cure it.
Autism is a lifelong condition, but you can make the most of it, and it is impossible to tell with any child how it will pan out.
You may want to ask your child's pediatrician about this. I am not a medical doctor but I do work with preschool children with autism and from what you describe your son is displaying some of the characteristics of autism.
Children with autism prefer solitary play, have repetitve behaviors, narrow interests, throw tantrums, limited eye contact, don't let others particpate in their activities, strict adherence to routines, sensory difficulties (it is like some sensory information actually "hurts": socks too tight, limited foods they will eat, etc.), things have to be placed a certain way (shoes put on a certain way, line up toys, toys put in certain spots, etc.), have difficulty sharing, often are echolalic (repeat exactly what you say but it isn't real communication), memorize scripted information (songs, lines from movies, etc.) but it is not used in a functional way or in context, and lack joint attention (example they point at something and look at you to see if you see it too) or does not adjust gaze to look at objects others are looking at.
Early intervention is key so I would urge you to see your doctor.